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Introduction Primary biliary cholangitis (PBC) is characterized by lymphocyte cell-induced immune destruction of cholangiole. However, the immunological characteristics of peripheral blood cells in PBC patients remain unknown. This study was designed to reveal the differences in the immunological characteristics between PBC patients and healthy adults. Methods We performed high-throughput sequencing to determine the TRB–CDR3 and IGH–CDR3 repertoires of T and B cells in 19 healthy controls and 29 PBC patients. Different immunological characteristics, such as distinctive complementarity determining region 3 (TRB–CDR3) lengths, usage bias of V and J segments, and random nucleotide addition were identified in PBC and healthy control (HC) groups. Results The diversity of TRB–CDR3 was significantly lower in the PBC group compared with the HC group. CDR3 and the N addition length distribution were significantly changed compared with the HC group. It appeared that the PBC group had more short N additions and the HC group had more long N additions in the TRB–CDR3 repertoire. The results also revealed a set of PBC-associated clonotypes compared with the HC group. Conclusion This study suggested that PBC is a complex autoimmune disease process with evidence of different TRB–CDR3 rearrangements compared with healthy adults that share IGH–CDR3 peptides with some autoimmune diseases. This new insight may contribute to a better understanding of the immune functions of PBC patients and benefit efficient applications of PBC diagnosis and treatments.

Psoriasis is a T cell-mediated chronic inflammatory skin disease with inflammatory cell infiltrates in the dermis and epidermis. Previous studies suggested that there are some expanded T-cell receptor (TCR) clones in psoriatic skin. However, the effect of psoriasis on the immunological characteristics of TCR in circulating blood has not been reported. To address this, we performed high-throughput sequencing to reveal the immunological characteristics of TCR beta chain (TRB) in both psoriasis patients and healthy controls. Our results revealed that the TRB-CDR3 region of psoriasis patients had distinctive immunological characteristics compared with that of healthy controls, including V gene usage, nt of N addition. In addition, three types of TRB-CDR3 peptides were found highly relevant to psoriasis. Our findings show the comprehensive characteristics of psoriasis on the TRB-CDR3 repertoire of circulating blood at sequence-level resolution. These findings may contribute to a better understanding of the pathogenesis of psoriasis and open opportunities to explore potential therapeutic targets.